LIfestyle MEtabotype Study A

Inclusion Criteria: * Overweight or obesity (BMI 25-40 kg/m²) * Good knowledge of German Exclusion Criteria: * Weight changes of more than 5% in the last 3 months * Night shift work * Travel across more than one time zone in the last month before and during study participation * Intensive regular physical activity of more than 2 hours per day * Current pregnancy or breastfeeding * Severe renal, liver or heart disease * Existing or past hematological malignancies, other malignant tumors, unless successfully treated more than 12 months before study start * Severe neurological or psychiatric disorders * Daily alcohol consumption of more than 20 grams or more than 150 grams per week * Use of illicit or legal drugs one week prior to study start and during study participation * Known systemic infections * Type 1 diabetes and rare forms of diabetes * Diabetes treatment with insulin or sulfonylureas or diabetes medication in the absence of manifest type 2 diabetes * Unstable thyroid dysfunction * Blood coagulation disorders or anticoagulation therapy that cannot be interrupted * Medications affecting nutrient absorption * Medications with immunosuppressants or steroids (oral or parenteral) * Current eating disorders, functional or structural digestive disorders or bariatric surgery * Food allergies or intolerances to ingredients of the test meals * Intermittent fasting or calorie-restricted diet four weeks prior to the start of the study or during the study * Ketogenic diet or ketogenic supplements four weeks prior to or during module B * Left-handedness * Severe claustrophobia * Electrical implants or non-removable metallic implants * Concurrent participation in another intervention study * Assessment by the study physician based on medical concerns precluding study participation